Am 20.08.2012 um 09:32 schrieb William Hay:

> On 18 August 2012 22:23, Reuti <[email protected]> wrote:
>> Am 17.08.2012 um 16:40 schrieb William Hay:
>> 
>>> We have a heterogenous cluster with several different types of node.
>>> We also have a couple of policies:
>>> i)Jobs won't run across multiple nodes of a given type if they can fit
>>> into a single node of that type.

With $fillup as allocation _rule and requesting excluisve access you should get 
the minimum amount of nodes.


>>> ii)Jobs that run across multiple nodes have exclusive access to those
>>> nodes while jobs that run within a single
>>> node share if sufficient resources are available.
>>> 
>>> A consequence of this is that some jobs get exclusive access to some
>>> nodes but not to others.  It's not a simple case of some nodes being
>>> bigger in all respects than others either.
>> 
>> Looking at ii) I don't understand this. Does a job spanning several nodes 
>> have exclusive access to *all* nodes of this job, or only when they fill all 
>> slots on this node? If there are leftover slots, they have to share the node 
>> with another job?
>> 
> Exclusive access to all nodes it runs on.  That's both desired and the
> effect of requesting an exclusive resource associated with a host.
> The idea here is that we don't want a multi-host job to run slow
> because it is being slugged by another job on a single host.  On the
> other hand we don't want to devote a whole 12 core node to a piddly
> single slot job.

You mean, if set up as outlined above, that the very last process of a parallel 
job would go to a node and maybe executed there alone. And for this very last 
one, you would allow additional jobs to be scheduled to?

-- Reuti

PS: Yeah, I have still some older mail left which I overlooked.
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